======================================
| [ 14.134839][ C2] #4: ffff88800a813358 (&br->multicast_lock){+.-.}-{3:3}, at: br_multicast_port_query_expired (./include/trace/events/../../../net/bridge/br_private.h:1293 ./include/trace/events/../../../net/bridge/br_private.h:1302 net/bridge/br_multicast.c:1906) bridge 
| [ 14.135372][ C2] #5: ffffffff9175b5c0 (rcu_read_lock_bh){....}-{1:3}, at: __dev_queue_xmit (./include/linux/bottom_half.h:20 ./include/linux/rcupdate.h:901 net/core/dev.c:4555) 
| [   14.135744][    C2]
| [   14.135744][    C2] stack backtrace:
[   14.136150][    C2] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[   14.136152][    C2] Workqueue: events_unbound linkwatch_event
[   14.136158][    C2] Call Trace:
[   14.136163][    C2]  <IRQ>
[ 14.136166][ C2] dump_stack_lvl (lib/dump_stack.c:123) 
[ 14.136173][ C2] lockdep_rcu_suspicious (kernel/locking/lockdep.c:6848) 
[ 14.136184][ C2] dev_hard_start_xmit (./include/net/net_namespace.h:418 ./include/linux/netdevice.h:2695 net/core/dev.c:2466 net/core/dev.c:3772 net/core/dev.c:3793) 
[ 14.136196][ C2] __dev_queue_xmit (net/core/dev.h:340 net/core/dev.c:4631) 
[ 14.136206][ C2] ? __build_skb_around (./arch/x86/include/asm/atomic.h:28 ./include/linux/atomic/atomic-arch-fallback.h:503 ./include/linux/atomic/atomic-instrumented.h:68 net/core/skbuff.c:381 net/core/skbuff.c:439) 
[ 14.136217][ C2] ? __pfx___dev_queue_xmit (net/core/dev.c:4538) 
[ 14.136219][ C2] ? __pfx___alloc_skb (net/core/skbuff.c:642) 
[ 14.136225][ C2] ? stack_trace_save (kernel/stacktrace.c:114) 
[ 14.136230][ C2] ? __pfx_stack_trace_save (kernel/stacktrace.c:114) 
[ 14.136238][ C2] ? __pfx___br_multicast_query_handle_vlan (net/bridge/br_multicast.c:909) bridge 
[ 14.136293][ C2] br_dev_queue_push_xmit (net/bridge/br_forward.c:34) bridge 
[ 14.136326][ C2] ? __pfx_br_dev_queue_push_xmit (net/bridge/br_forward.c:34) bridge 
[ 14.136358][ C2] ? br_multicast_count (./arch/x86/include/asm/bitops.h:206 ./arch/x86/include/asm/bitops.h:238 ./include/asm-generic/bitops/instrumented-non-atomic.h:142 ./include/trace/events/../../../net/bridge/br_private.h:764 net/bridge/br_multicast.c:5052) bridge 
[ 14.136398][ C2] __br_multicast_send_query (net/bridge/br_multicast.c:1813) bridge 
[ 14.136443][ C2] ? __pfx___br_multicast_send_query (net/bridge/br_multicast.c:1789) bridge 
[ 14.136484][ C2] ? __lock_acquire (kernel/locking/lockdep.c:5228) 
[ 14.136495][ C2] ? br_multicast_send_query (net/bridge/br_multicast.c:1891) bridge 
[ 14.136529][ C2] br_multicast_send_query (net/bridge/br_multicast.c:1891) bridge 
[ 14.136568][ C2] ? __pfx_br_multicast_send_query (net/bridge/br_multicast.c:1852) bridge 
[ 14.136601][ C2] ? br_multicast_port_query_expired (./include/trace/events/../../../net/bridge/br_private.h:1293 ./include/trace/events/../../../net/bridge/br_private.h:1302 net/bridge/br_multicast.c:1906) bridge 
[ 14.136638][ C2] ? __pfx_br_ip4_multicast_port_query_expired (net/bridge/br_multicast.c:1920) bridge 
[ 14.136673][ C2] ? __pfx_lock_acquire.part.0 (kernel/locking/lockdep.c:5816) 
[ 14.136679][ C2] ? do_raw_spin_lock (./arch/x86/include/asm/atomic.h:107 ./include/linux/atomic/atomic-arch-fallback.h:2170 ./include/linux/atomic/atomic-instrumented.h:1302 ./include/asm-generic/qspinlock.h:111 kernel/locking/spinlock_debug.c:116) 
[ 14.136684][ C2] ? __pfx_do_raw_spin_lock (kernel/locking/spinlock_debug.c:114) 
[ 14.136687][ C2] ? lock_acquire (kernel/locking/lockdep.c:5824) 
[ 14.136690][ C2] ? br_multicast_port_query_expired (./include/trace/events/../../../net/bridge/br_private.h:1293 ./include/trace/events/../../../net/bridge/br_private.h:1302 net/bridge/br_multicast.c:1906) bridge 
[ 14.136731][ C2] ? br_multicast_port_query_expired (net/bridge/br_multicast.c:1917) bridge 
[ 14.136764][ C2] br_multicast_port_query_expired (net/bridge/br_multicast.c:1917) bridge 
[ 14.136801][ C2] ? __pfx_br_ip4_multicast_port_query_expired (net/bridge/br_multicast.c:1920) bridge 
[ 14.136835][ C2] call_timer_fn (kernel/time/timer.c:1789) 
[ 14.136838][ C2] ? call_timer_fn (./include/linux/lockdep.h:31 kernel/time/timer.c:1779) 
[ 14.136841][ C2] ? call_timer_fn (./include/linux/lockdep.h:31 kernel/time/timer.c:1779) 
[ 14.136845][ C2] ? __pfx_call_timer_fn (kernel/time/timer.c:1766) 
[ 14.136849][ C2] ? hlock_class (./arch/x86/include/asm/bitops.h:227 ./arch/x86/include/asm/bitops.h:239 ./include/asm-generic/bitops/instrumented-non-atomic.h:142 kernel/locking/lockdep.c:230) 
[ 14.136858][ C2] ? mark_held_locks (kernel/locking/lockdep.c:4323) 
[ 14.136870][ C2] __run_timers (kernel/time/timer.c:1841 kernel/time/timer.c:2414) 
[ 14.136874][ C2] ? __pfx_br_ip4_multicast_port_query_expired (net/bridge/br_multicast.c:1920) bridge 
[ 14.136916][ C2] ? __pfx___run_timers (kernel/time/timer.c:2385) 
[ 14.136918][ C2] ? clockevents_program_event (kernel/time/clockevents.c:326) 
[ 14.136928][ C2] ? do_raw_spin_lock (./arch/x86/include/asm/atomic.h:107 ./include/linux/atomic/atomic-arch-fallback.h:2170 ./include/linux/atomic/atomic-instrumented.h:1302 ./include/asm-generic/qspinlock.h:111 kernel/locking/spinlock_debug.c:116) 
[ 14.136932][ C2] ? __pfx_do_raw_spin_lock (kernel/locking/spinlock_debug.c:114) 
[ 14.136936][ C2] ? lock_acquire (kernel/locking/lockdep.c:5824) 
[ 14.136939][ C2] ? run_timer_softirq (kernel/time/timer.c:2426 kernel/time/timer.c:2418 kernel/time/timer.c:2435 kernel/time/timer.c:2445) 
[ 14.136950][ C2] run_timer_softirq (kernel/time/timer.c:2427 kernel/time/timer.c:2418 kernel/time/timer.c:2435 kernel/time/timer.c:2445) 
[ 14.136955][ C2] handle_softirqs (kernel/softirq.c:561) 
[ 14.136962][ C2] ? do_raw_spin_unlock (./arch/x86/include/asm/atomic.h:23 ./include/linux/atomic/atomic-arch-fallback.h:457 ./include/linux/atomic/atomic-instrumented.h:33 ./include/asm-generic/qspinlock.h:57 kernel/locking/spinlock_debug.c:101 kernel/locking/spinlock_debug.c:141) 
[ 14.136969][ C2] __irq_exit_rcu (kernel/softirq.c:596 kernel/softirq.c:435 kernel/softirq.c:662) 
[ 14.136973][ C2] irq_exit_rcu (kernel/softirq.c:680) 
[ 14.136976][ C2] sysvec_apic_timer_interrupt (arch/x86/kernel/apic/apic.c:1049 arch/x86/kernel/apic/apic.c:1049) 
[   14.136980][    C2]  </IRQ>
[   14.136981][    C2]  <TASK>
[ 14.136983][ C2] asm_sysvec_apic_timer_interrupt (./arch/x86/include/asm/idtentry.h:702) 
[ 14.136988][ C2] RIP: 0010:_raw_spin_unlock_irqrestore (./include/linux/spinlock_api_smp.h:152 kernel/locking/spinlock.c:194) 
[ 14.136991][ C2] Code: 10 e8 b1 3d 87 fd 48 89 ef e8 f9 ad 87 fd 81 e3 00 02 00 00 75 1d 9c 58 f6 c4 02 75 29 48 85 db 74 01 fb 65 ff 0d b5 0d 8f 6f <74> 0e 5b 5d c3 cc cc cc cc e8 2f df ac fd eb dc 0f 1f 44 00 00 5b
All code
========
   0:	10 e8                	adc    %ch,%al
   2:	b1 3d                	mov    $0x3d,%cl
   4:	87 fd                	xchg   %edi,%ebp
   6:	48 89 ef             	mov    %rbp,%rdi
   9:	e8 f9 ad 87 fd       	call   0xfffffffffd87ae07
   e:	81 e3 00 02 00 00    	and    $0x200,%ebx
  14:	75 1d                	jne    0x33
  16:	9c                   	pushf
  17:	58                   	pop    %rax
  18:	f6 c4 02             	test   $0x2,%ah
  1b:	75 29                	jne    0x46
  1d:	48 85 db             	test   %rbx,%rbx
  20:	74 01                	je     0x23
  22:	fb                   	sti
  23:	65 ff 0d b5 0d 8f 6f 	decl   %gs:0x6f8f0db5(%rip)        # 0x6f8f0ddf
  2a:*	74 0e                	je     0x3a		<-- trapping instruction
  2c:	5b                   	pop    %rbx
  2d:	5d                   	pop    %rbp
  2e:	c3                   	ret
  2f:	cc                   	int3
  30:	cc                   	int3
  31:	cc                   	int3
  32:	cc                   	int3
  33:	e8 2f df ac fd       	call   0xfffffffffdacdf67
  38:	eb dc                	jmp    0x16
  3a:	0f 1f 44 00 00       	nopl   0x0(%rax,%rax,1)
  3f:	5b                   	pop    %rbx

Code starting with the faulting instruction
===========================================
   0:	74 0e                	je     0x10
   2:	5b                   	pop    %rbx
   3:	5d                   	pop    %rbp
   4:	c3                   	ret
   5:	cc                   	int3
   6:	cc                   	int3
   7:	cc                   	int3
   8:	cc                   	int3
   9:	e8 2f df ac fd       	call   0xfffffffffdacdf3d
   e:	eb dc                	jmp    0xffffffffffffffec
  10:	0f 1f 44 00 00       	nopl   0x0(%rax,%rax,1)
  15:	5b                   	pop    %rbx
[   14.136994][    C2] RSP: 0018:ffffc900003df780 EFLAGS: 00000282
[   14.136997][    C2] RAX: 0000000000000006 RBX: 0000000000000200 RCX: 1ffffffff27066b1
[   14.136999][    C2] RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffff9074b761
[   14.137000][    C2] RBP: ffff888001040f40 R08: 0000000000000001 R09: fffffbfff2705be1
[   14.137002][    C2] R10: ffffffff9382df0f R11: ffff8880054b45c0 R12: ffff888001040f40
[   14.137004][    C2] R13: ffffea00002eae00 R14: ffff888001043240 R15: ffff88800babb800
[ 14.137016][ C2] ? _raw_spin_unlock_irqrestore (./include/linux/spinlock_api_smp.h:151 kernel/locking/spinlock.c:194) 
[ 14.137024][ C2] get_partial_node.part.0 (mm/slub.c:2870) 
[ 14.137039][ C2] ___slab_alloc (mm/slub.c:2831 mm/slub.c:2948 mm/slub.c:3806) 
[ 14.137042][ C2] ? __create_object (mm/kmemleak.c:766) 
[ 14.137047][ C2] ? __alloc_skb (net/core/skbuff.c:669) 
[ 14.137051][ C2] ? get_any_partial (./include/linux/seqlock.h:72 ./include/linux/cpuset.h:144 mm/slub.c:2909) 
[ 14.137061][ C2] ? mark_held_locks (kernel/locking/lockdep.c:4323) 
[ 14.137072][ C2] ? __kmalloc_node_track_caller_noprof (mm/slub.c:3916 mm/slub.c:3991 mm/slub.c:4152 mm/slub.c:4293 mm/slub.c:4313) 
[ 14.137076][ C2] __kmalloc_node_track_caller_noprof (mm/slub.c:3916 mm/slub.c:3991 mm/slub.c:4152 mm/slub.c:4293 mm/slub.c:4313) 
[ 14.137080][ C2] ? __create_object (mm/kmemleak.c:766) 
[ 14.137085][ C2] ? __alloc_skb (net/core/skbuff.c:669) 
[ 14.137092][ C2] kmalloc_reserve (net/core/skbuff.c:603) 
[ 14.137101][ C2] __alloc_skb (net/core/skbuff.c:669) 
[ 14.137105][ C2] ? __pfx___alloc_skb (net/core/skbuff.c:642) 
[ 14.137113][ C2] ? rt6_sync_up (net/ipv6/route.c:4797) 
[ 14.137118][ C2] ? __pfx_rt6_sync_up (net/ipv6/route.c:4797) 
[ 14.137126][ C2] inet6_ifinfo_notify (./include/linux/skbuff.h:1339 ./include/net/netlink.h:1019 net/ipv6/addrconf.c:6161) 
[ 14.137134][ C2] addrconf_notify (net/ipv6/addrconf.c:3765 (discriminator 2)) 
[ 14.137142][ C2] notifier_call_chain (kernel/notifier.c:85 (discriminator 2)) 
[ 14.137154][ C2] netdev_state_change (net/core/dev.c:1538 net/core/dev.c:1529) 
[ 14.137158][ C2] ? __pfx_netdev_state_change (net/core/dev.c:1530) 
[ 14.137174][ C2] linkwatch_do_dev (net/core/link_watch.c:186) 
[ 14.137178][ C2] __linkwatch_run_queue (./include/linux/spinlock.h:376 net/core/link_watch.c:245) 
[ 14.137185][ C2] ? __pfx___linkwatch_run_queue (net/core/link_watch.c:195) 
[ 14.137192][ C2] ? lock_acquire (kernel/locking/lockdep.c:5824) 
[ 14.137202][ C2] linkwatch_event (net/core/link_watch.c:287) 
[ 14.137204][ C2] process_one_work (kernel/workqueue.c:3238) 
[ 14.137218][ C2] ? __pfx___lock_release (kernel/locking/lockdep.c:5503) 
[ 14.137224][ C2] ? __pfx_process_one_work (kernel/workqueue.c:3140) 
[ 14.137237][ C2] ? assign_work (kernel/workqueue.c:1200) 
[ 14.137247][ C2] worker_thread (kernel/workqueue.c:3313 kernel/workqueue.c:3400) 
[ 14.137261][ C2] ? __pfx_worker_thread (kernel/workqueue.c:3346) 
[ 14.137267][ C2] kthread (kernel/kthread.c:464) 
[ 14.137272][ C2] ? __pfx_kthread (kernel/kthread.c:413) 
[ 14.137281][ C2] ? __pfx_kthread (kernel/kthread.c:413) 
[ 14.137287][ C2] ret_from_fork (arch/x86/kernel/process.c:148) 
[ 14.137291][ C2] ? __pfx_kthread (kernel/kthread.c:413) 


Finger prints:
lockdep_rcu_suspicious:dev_hard_start_xmit:__dev_queue_xmit:br_dev_queue_push_xmit:__br_multicast_send_query